# Equivalency: particle with energy

1. Dec 30, 2009

### Pythagorean

from wiki:
E=mc^2

I'm still having trouble conceptualizing this equivalence. If the wiki article speaks true:

If a particle is in a higher energy state, it's actually more massive than the same particle in a lower energy state?

2. Dec 30, 2009

### tiny-tim

Yup!

A spinning flywheel is "heavier" to push than a non-spinning one.

If a body absorbs radiation by heating up, it is more massive.

Same if it absorbs radiation by having electrons in more energetic states.

3. Dec 30, 2009

### Pythagorean

That sounds like an inertial statement. What about gravity? Is the force between a higher-energy particle and the Earth greater than a force between the same particle (in a lower energy state) and the Earth?

So does this mean that somewhere down the line we will be able to construct a mass generator and exploit dm/dt in all kinds of different ways?

4. Dec 30, 2009

### tiny-tim

It is an inertial statement.
Now you're talking about the equivalence principle, of general relativity, and the equality of inertial mass and gravitational mass â€¦

I suspect the wikipedia article (you didn't provide a link) is only talking about inertial mass and special relativity.
Sorry, not following you.

5. Dec 30, 2009

### Pythagorean

ok, separating the two helps, thanks.

In terms of technology I was asking if it implied that we could theoretically create matter with electricity one day.